Email, Messaging, & Video Calls Email Start Mozilla Thunderbird in Safe Mode by Heinz Tschabitscher Writer A former freelance contributor who has reviewed hundreds of email programs and services since 1997. our editorial process Heinz Tschabitscher Updated on February 25, 2020 Mozilla Email Yahoo! Mail Gmail Tweet Share Email Is Mozilla Thunderbird refusing to start and showing a cryptic error message—or nothing at all? Don't panic, at least not yet. Chances are a troublesome extension is wreaking havoc. Get rid of the extension and you rid Mozilla Thunderbird of its problems. How, though, can one uninstall an add-on without the menus and dialogs in Mozilla Thunderbird that make that possible? Fortunately, Mozilla Thunderbird includes a "safe" mode that disables all extensions before (hopefully) launching the application. You can then uninstall problematic extensions. Start Mozilla Thunderbird in Safe Mode to Uninstall Broken Extensions To launch Mozilla Thunderbird in Safe Mode and get rid of extensions that cause problems, first make sure Mozilla Thunderbird is not running. Then, follow the instructions below for your operating system. For Windows Users Select Mozilla Thunderbird (Safe Mode) from Start | All Programs | Mozilla Thunderbird.If you do not have that entry in your Start menu:Press Windows-R.Type thunderbird -safe-mode Click OK. For Mac OS X Users Launch Terminal (type terminal in Spotlight search and click Terminal under Applications in the search results).Type thunderbird in the Spotlight menu bar search field.Click Show All.Drag and drop Thunderbird from the Applications category to the Terminal window.Append Contents/MacOS/thunderbird-bin -safe-mode to Thunderbird.app/Make sure you delete the white space character at the end of Thunderbird.app/ before completing the command line.If Mozilla Thunderbird is installed in the default applications directory, the command line will be /Applications/Thunderbird.app/Contents/MacOS/thunderbird-bin -safe-modePress Enter. For Linux Users Type [path to Mozilla Thunderbird]/thunderbird -safe-mode at a command line.You can find the full path to Mozilla Thunderbird by typing which thunderbird at a command prompt followed by Enter.Press Enter.Select Tools | Add-ons from the menu in Mozilla Thunderbird.Go to the Extensions category.Highlight the troubling extension.Click Uninstall.Click Uninstall again.Shut down Mozilla Thunderbird.